Journal of cataract and refractive surgery最新文献

Purpose: To assess whether the power of intraocular lenses (IOLs) can still be accurately measured after hemidissection, by comparing the measurements of intact lenses with those of the hemidissected lenses.

Setting: A university tertiary referral hospital.

Design: A laboratory study.

Methods: Monofocal (n=8), extended-depth-of-focus (EDoF) (n=2), and trifocal IOLs (n=2) from leading manufacturers were evaluated. The power of each IOL was assessed in the intact state and following hemidissection under room-temperature conditions. Subsequently, optical evaluation was performed with a single half (the larger part) placed in a model eye, and then with both halves reassembled, aligning the adjacent edges along the hemidissection line. A one-way analysis of variance (ANOVA) was used to compare repeated measures across these conditions.

Results: Upon evaluating the powers of the IOLs, no statistically significant differences were observed among the intact, one-half, and two-halves conditions (p = 0.77). The majority of post-hemidissection power measurements fell within the ISO tolerance range. On average, the differences in power before and after hemidissection were minimal, measuring approximately 0.15 ± 0.17 D for monofocal, 0.10 ± 0.07 D for EDoF, and 0.02 ± 0.01 D for trifocal IOLs.

Conclusions: The power of a hemidissected IOL can be accurately assessed. Measuring one half of a hemidissected IOL provides results that are comparable to those from evaluating both halves, thus accurately reflecting the power of the intact ones. This study suggests that confirming a deviation in power of an explanted lens is a viable option despite the physical damage caused by explantation procedures.

Purpose: To evaluate explanted hydrophilic acrylic phakic intraocular lenses (PIOLs) for evidence of calcification, specifically the Implantable Collamer Lens (ICL; Staar Surgical, Monrovia, CA, USA) and the I-CARE (Corneal, Paris, France).

Setting: Intermountain Ocular Research Center, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

Design: Retrospective laboratory analysis of explanted PIOLs.

Methods: Demographic data from the explanted cases was collected through retrospective chart review. Explanted hydrophilic acrylic PIOLs were examined by gross and light microscopy to evaluate optical clarity, material integrity, and presence of surface or subsurface deposits. A subset of lenses underwent histochemical staining (1% alizarin red) and surface analysis to detect calcium deposits. Additional lenses were analyzed with implant cytology and visible-light transmission testing to assess biological deposition and ultraviolet (UV) blocking capacity.

Results: Eighty-four PIOLs were analyzed, including 65 ICLs (mean implantation time 8.78 ± 7.23 years) and 19 I-CARE lenses (mean implantation time 12.99 ± 5.34 years). Trace to mild pigmentary deposition was present in 36 ICLs (55.4%) and 10 I-CARE lenses (52.6%). No opacification or calcification was observed on gross or microscopic evaluation, including peripheral haptic areas. Histochemical staining and surface analysis confirmed absence of calcium deposits. Implant cytology revealed proteinaceous material without cellular components. Light transmission ranged from 93.7% to 97.4%, and all lenses demonstrated effective UV blocking.

Conclusions: This large series of explanted hydrophilic acrylic PIOLs showed no evidence of calcification after long-term implantation. These findings support the material stability and biocompatibility of hydrophilic acrylic PIOLs in vivo.

Purpose: To assess by an in vitro model the influence of antibiotic agent and bacterial load upon the failure of intracameral endophthalmitis prophylaxis.

Setting: Microbiology laboratory.

Design: Bacterial growth comparison.

Methods: Bacteria were incubated with moxifloxacin, cefuroxime, ceftazidime or imipenem. Antibiotic concentrations were approximately twice those achieved by standard clinical intracameral doses. Bacterial loads were either low or high (0.0025 or 0.25 McFarland). The tested strains included 4 Enterococcus faecium, 7 Klebsiella pneumoniae, 8 methicillin-resistant Staphylococcus aureus, 3 Streptococcus pneumoniae, and 6 Pseudomonas aeruginosa. Samples were diluted by half every 2 hours to model the half-life of intracameral antibiotics. Bacterial broths were plated at 24 hours, and colonies were counted at 48 hours. Samples with >250 colony forming units/mL (CFU/mL) were deemed failures.

Results: Antibiotics that successfully eliminated a pathogen often failed when the bacterial load was 100 times greater. Moxifloxacin had no failures against low load pathogens. Moxifloxacin and ceftazidime both had significantly fewer failures than cefuroxime (p<0.01; p>0.02). Ceftazidime was far more effective than cefuroxime against gram negatives, but less effective against low load enterococci.

Conclusions: High bacterial loads can multiply uncontrollably in the presence of antibiotics which are effective when the bacterial load is lower; this underscores the importance of uncontaminated equipment and ocular surface antisepsis. Broadest coverage against common postoperative endophthalmitis pathogens was demonstrated by moxifloxacin and ceftazidime.

Purpose: To evaluate the prediction accuracy of intraocular lens (IOL) calculation formulas in primary IOL fixation using the Yamane technique, and explore adjustment strategies to improve the refractive outcomes.

Setting: Zhongshan ophthalmic center, Guangzhou, China.

Design: Retrospective case series.

Methods: 50 eyes from 50 patients with inadequate capsular support who underwent lens extraction and primary Yamane IOL fixation were reviewed. The predictive accuracy of 7 formulas, Barrett Universal II (BU II), Emmetropia Verifying Optical (EVO), Kane, SRK/T, Holladay 1, Hoffer Q and Haigis, were evaluated with or without lens constant optimization.

Results: Before lens constants optimization, SRK/T, holladay 1, Hoffer Q, BU II and EVO formulas exhibited statistically significant hyperopic mean PEs (range: 0.26 - 0.44 D, all P < 0.05), whereas the Haigis and Kane formulas showed relatively better accuracy without significant hyperopic shift. The mean absolute error (MAE) of all formulas ranged from 0.47 to 0.65D, and the percentage of eyes with PE with ± 0.50D ranged from 40% to 60%. After lens constants optimization, the BU II and SRK/T formulas exhibited the lowest MAE (0.43 and 0.47, respectively), with the highest percentage of PE within ± 0.50 D (64% and 64%, respectively).

Conclusion: Before lens constant optimization, BU II, EVO, SRK/T, Holladay 1, Hoffer Q all produced significantly hyperopic PEs in primary Yamane IOL fixation. After lens constants optimizing, the BU II and SRK/T displayed better performance. To enhance refractive outcomes in these patients, a slightly myopia target refraction or optimize the lens constants was recommended.

Purpose: To evaluate refractive growth following intraocular lens (IOL) implantation for Marfan syndrome (MFS) patients with ectopia lentis (EL) and identify influencing factors.

Setting: Eye and ENT Hospital of Fudan University, Shanghai, China.

Design: Retrospective cohort study.

Methods: Medical data were collected from patients diagnosed with MFS and EL underwent IOL implantation. Spherical equivalent (SE) and ocular biometric parameters were recorded preoperatively and serially postoperatively. The rate of refractive growth (RRG3) were calculated using aphakic refraction at the IOL plane against log10(age+0.6) years. Patients were stratified by surgical age with multivariate generalized estimating equation (GEE) analyses identifying predictive factors.

Results: A total of 374 eyes of 232 patients were enrolled in this study. Median age at surgery was 6.38 years (Interquartile range [IQR]:5.00-11.60), with a median follow-up of 3.17 years (IQR:2.17-4.54). The mean △SE/△AL was -2.04±1.84 diopter(D)/mm. The RRG3 model effectively controlled for age demonstrating a mean value of -14.1±10.2D. Greater postoperative myopia at baseline (β=0.849, P=0.022) and poorer postoperative best-corrected visual acuity (β=-10.333, P=0.001) were associated with more negative RRG3 value in patients aged ≤8 years. In patients aged 8-15 years at surgery, RRG3 was only correlated with postoperative SE (β=1.812, P<0.001). Age at surgery, IOL fixation technique and preoperative ocular biometrics were not significantly associated with RRG3.

Conclusion: Refraction growth of MFS eyes with EL undergoing primary IOL implantation followed a logarithmic progression. Postoperative refractive status and visual acuity significantly influence refractive growth, underscoring the importance of careful postoperative monitoring and strategic undercorrection setting.

Purpose: To evaluate whether preceding Hydrus Microstent implantation with canaloplasty improves the rate of successful device positioning and reduces the incidence of device malposition.

Setting: Private glaucoma referral center, United States.

Design: Retrospective comparative cohort study.

Methods: This study included 368 eyes undergoing phacoemulsification with Hydrus implantation, with or without prior canaloplasty using the OMNI Surgical System. The primary outcome was the rate of successful Hydrus implantation, defined as the absence of both downward tip malposition and intraoperative insertion failure. Complication rates were compared between groups using appropriate statistical analyses.

Results: Of 368 eyes, 236 received Hydrus alone and 132 underwent canaloplasty followed by Hydrus. Successful implantation occurred in 206 of 236 eyes (87.3%) in the Hydrus-only group and 124 of 132 eyes (93.9%) in the Canaloplasty + Hydrus group (p = 0.048). Downward tip malposition occurred in 21 of 236 eyes (8.9%) versus 5 of 132 eyes (3.8%), and insertion failure occurred in 9 of 236 eyes (3.8%) versus 3 of 132 eyes (2.3%) in the Hydrus-only and Canaloplasty + Hydrus groups, respectively; these subgroup differences were not statistically significant. However, the downward malposition rate demonstrated a 57% relative risk reduction in the canaloplasty group.

Conclusion: Preceding Hydrus implantation with canaloplasty was associated with improved technical delivery success, reflected by reduced downward tip malposition and fewer insertion failures. Canaloplasty was also associated with an unexpected, distinct type of malposition, highlighting the importance of recognizing different malposition patterns and careful intraoperative assessment.